Dr Robert Moog, the inventor of the electronic synthesiser, has died of brain cancer aged 71.

His synthesiser, which bears his name, revolutionised music from the 1960s onwards, and was used by bands like the Beatles and the Doors.

Today, the electronic manipulation of sound is a ubiquitous feature of popular music. This was not always the case, and Moog was one of the pivotal pioneers of synthesised sound.

His instruments transformed pop music during that most revolutionary and experimental of times, the 1960s.

Born in the New York City suburb of Queens in 1934, Robert Moog - the name rhymes with "vogue" - became fascinated with electronics as a child.

The Minimoog proved popular among 'progressive' rockers

Aged just 14, and encouraged by his father, George, Moog built his first electronic instrument, a theremin.

In 1954, Moog - then 19 - and his father, started their own company, RA Moog, selling theremin kits, price $49.95 by mail order, from their home.

Alongside his hobby, Moog was studying hard. From the Bronx High School of Science, he went on to Queens College, before graduating in electrical engineering at Columbia University and earning a doctorate in engineering physics at Cornell.

Although RCA had already built a musical synthesiser, it was a vast beast, and never intended for sale.

Frank Zappa was a Moog fan

What Moog did, in 1964, was to produce and market a practical instrument, a small keyboard synth which could be used with relative ease.

"I didn't know what the hell I was doing," Moog later recalled. "I was doing this thing to have a good time, then all of a sudden someone's saying to me, 'I'll take one of those and two of that.' That's how I got into business."

Hollywood soon expressed an interest, but it was Wendy Carlos' 1968 Grammy-winning album, Switched-On Bach, which brought the Moog synthesiser to spectacular prominence.

Before long many musicians and groups, including the Doors, the Grateful Dead, the Rolling Stones and the Beatles, were using Moog synthesisers. Keith Emerson, of Emerson, Lake and Palmer, was the first musician to use one for live concerts.

But the boom days were not to last. Even though the Minimoog, a stripped-down version of the original instrument and beloved by artists like Rick Wakeman, made waves when it came out in 1970, the writing was on the wall.

Moog was always fascinated by electronics

With interest in purely electronic sound falling, and huge competition from other synthesiser manufacturers, most notably ARP Instruments and Electronic Music Studios, the bottom fell out of the market.

"Suddenly we went from a nine-month or a year backlog to having no backlog and no orders," Moog said. "I ran out of money at the beginning of 1971."

He sold a controlling interest in his struggling company and, more important, rights to the Moog Music name to a venture capitalist.

In 1978, he started a new company, Big Briar, building custom instruments and sound-effect boxes.

Even so, many musicians, including Brian Eno, Frank Zappa, The Cure and Fat Boy Slim, sought the Moog sound, keeping it alive, even as analogue synthesisers were wiped-out by their digital cousins.

After a lengthy legal battle, Moog reclaimed the rights to the Moog brand in 2002 and began selling instruments bearing his name for the first time in more than two decades.